The present invention relates to electromechanical counters adapted to be operated by discrete pulses of electric power originating from a source remote from the counter location. An example of such a counter is the one disclosed in U.S. Pat. No. 3,700,163 dated Oct. 24, 1972. In the metering of utilities supplied to private residences such as electricity, gas and water it is sometimes desirable, particularly in the northern latitudes to prevent meter freeze-up in the case of water, to locate the meters within the house. When this is done, however, with conventional meters which have the counter associated with the meter itself, it is necessary for the meter reader to gain access to the house in order to take periodic readings. Such access is not always readily available to the meter reader; however, because of a number of reasons such as absence of the owner or, in some cases, reluctance of the owner to willingly give such access. Therefore, it is desirable to provide a counter which can be mounted outside of the residence structure and which is electrically connected to a pulse producing means included as part of the metering mechanism within the residence. For a variety of reasons it is desirable that such pulse producing means be of self-generating type, that is, not dependent on house power to produce the pulse which is to be transmitted to the remote counter. An example of a meter provided with such a pulse producing means of the self-generating type is disclosed in U.S. Pat. No. 3,685,353 dated Aug. 22, 1972.
While pulse generators of the type therein disclosed have the advantage of being self-contained, compact and not dependent on the house power, the magnitude of the power pulses which they are capable of producing is limited by the load which may be imposed on the meter to drive the generator. If the generator were to impose too high a load on the meter, its accuracy would be adversely affected and performance would not conform to industry standards. Therefore, since the magnitude of the power of the pulse must be held to a minimum, the remote counter must be capable of reliable operation in response to pulses of a relatively low power level. Typical of the prior art counters is the one shown in U.S. Pat. No. 3,725,648 dated Apr. 3, 1973. As there shown, an electric coil is energized to induce pivotal motion of a pole plate 40 (clapper) which in turn causes pivotal motion of a ratchet arm 36 Z(verge) which is drive connected to a series of counter wheels. The verge is biased to its initial position by means of a spring 38. When a pulse is received in the coil it is energized and the clapper pivots to cause pivotal motion of the verge against the bias of spring 38 to drive the counter. When the coil is de-energized the spring returns the verge and clapper to their initial positions. Because of the lower power levels at which such counters must operate when energized from remote self-generating devices, the movable parts must be as light in weight as possible and the bias of the spring which must be overcome should be as small as possible.
Another requirement of such counters is that they be relatively immune from the effects of shocks; that is, that they should not operate to advance the counter wheels when shocks or blows are imposed on the counter or its housing. Counters of the type shown for example in Pat. No. 3,700,163 are usually adapted to operate in connection with pulse generating means which produce pulses having a power level of relatively large magnitude. When this is the case, relative immunity from shock can be achieved by simply providing a biasing spring which imposes a bias of succicient force to prevent operation when shocks are imposed on the counting mechanism. However, when a counter must operate in response to a pulse having a relatively low power level, such high biasing forces cannot be accepted simply because the power to operate the counter against such high biasing forces is not available. A proposed solution to the problem hereinabove defined is described in U.S. Pat. No. 3,619,577 dated Nov. 9, 1971. However, the counter disclosed has certain advantages in that it does not provide insensitivity to all types of shocks which such counters may be subjected to.